shimy182: You should be taking away 2 pounds from 27 and not adding it to get the total cost of £25 pounds
Each of them originally pay 10 each, so 30, they get 1 pound back, so they spend 9*3 = 27, and the bell boy TOOK 2 pounds, which would have otherwise gone back to the customers, so they would have spent less than £9 each and this is then timed by 3 .. long sentence ... so you should subtract the 2 quid from 27 and not add it, it doesn't make sense to do this.